Subversion of FLS2 subcellular transport by the bacterial effector HopM1.
J. LOISEAU (1), M. Schattat (2) (1) The Sainsbury Laboratory, United Kingdom; (2) Martin Luther University Halle-Wittenberg, Germany

The Flagellin Sensing 2 (FLS2) receptor kinase is a primary sensor of the plant’s immune system, and presented at the plasma membrane to recognize bacterial flagellin (flg22) and trigger anti-bacterial immunity. Upon flg22 recognition, FLS2 induces a series of defence outputs and enters the endocytic pathway trafficking via the trans-Golgi network/early endosome (TGN/EE) and late endosome/multi-vesicular body (LE/MVB) for vacuolar degradation. To promote infections success, bacterial pathogens secrete effectors inside plant cells that interfere with FLS2 signaling and defences. Therefore the elements of the subcellular transport pathways are critical for plant immunity and are bona fide targets of pathogen effectors. However, effector interference with FLS2 trafficking remains poorly understood. Here, we present that the P. syringae effector HopM1 impairs flg22-induced endocytosis of FLS2 in N. benthamiana. We show that HopM1 does not affect the localisation of the LE/MVB marker ARA7/Rab F2b but alters the localisation and expression of the TGN/EE marker SYP61, known to co-localise with endosomal FLS2. To characterize the molecular mechanisms underlying the HopM1-mediated interference of FLS2 endocytosis, we focus on AtMIN7, a TGN-localized guanine-nucleotide exchange factor for ADP-ribosylation factor GTPases (ARF-GEF), previously described as required for HopM1 virulence in Arabidopsis. We provide evidences that flg22-induced endocytosis and degradation of FLS2 are altered in min7 mutant plants. This suggests that AtMIN7 is required for FLS2 post-TGN trafficking, and we are currently investigating the molecular basis by which AtMIN7 facilitates HopM1 interference with FLS2 post-TGN trafficking.

Abstract Number: P7-189
Session Type: Poster